# MCNPX dose result is too small

Tags:
1. Mar 2, 2015

### Kim Jae ryang

I want to calculate absorbed dose by MCNP and phantom.
describe x-ray tube and set radiation filed is 30cm x 30cm
I use SRS-78, describe sorce card. 100kev 20mAs 14degree target is tungsten and film is Al 3mm.

I use *f6 tally
so I convert jerk/g ->Mev/g use 1Mev = 1.60E-22jerk
and then Mev/g->Gy use 1gy=6.24E+07mev/g
finallt comply photon number, electron's number (0.02A/1.602*10-19c) * electron->phton convert percentage (0.002072)

then ESD is 1.08E-30 -> 0.027882mGy
and real esd is 2.41mGy... my result is too small... ;(

Code (Text):

cell card
666 0   11 -12 13 -14 16 -17  fill=1000  imp:p,e=1 $phantom box *trcl=(0 0 0 180 90 90 90 0 90 90 90 180 999 0 99 imp:p,e=0$ exterior - zero importance
101 101 -11.34 -110 120 310              imp:p,e=1                               $out 201 201 -1e-20 -120 #310 imp:p,e=1$ in
310 201 -1e-20 -310                      imp:p,e=1                               $hole 401 401 -1.19 -401 imp:p,e=1$ table
255 301 -4.0866e-05 -255 imp:p,e=1
888 301 -4.0866e-05  -99 #101 #310 #201 401 255 #666  imp:p,e=1                            $remainder C ****************************************************************************** C Surface cards C ****************************************************************************** 7 rpp 0 0.40702 0 0.40702 0 0.41494 11 px -26.4563$ phantom box
12  px  26.4563
13  py -10.98954
14  py  10.98954
16  pz -85.47764
17  pz  85.47764
99  so  200  $exterior boundary 401 rpp -30 30 10.99 15.99 -90 120$ table
c 310 arb -0.75 -95 26.5   -0.75 -95 23.5    0.75 -95 26.5    0.75 -95 23.5 &
c          -1.05 -93 26.8   -1.05 -93 23.2   1.05 -93 26.8   1.05 -93 23.2 &
c          1234 5678 1256 2367 3478 1458
310 arb -1.05 -93 26.8  -1.05 -93 23.2  1.05 -93 26.8  1.05 -93 23.2
0 -100 25 0 0 0 0 0 0 0 0 0 1234 1250 1350 2450 3450 0
110 rpp -10 10 -105 -93  0 60                                                   $out 120 rpp -7 7 -103 -95 3 57$ in
255 rpp -10 10  -11.15 -10.99 5 45                                             $dosimeter C ****************************************************************************** C Data cards C ****************************************************************************** mode p c ***************************external source definition ************************ sdef erg=d1 par=p vec=0 1 0 x=d2 y=-100 z=d3 # si1 sp1$ 100kev/photon per
H       D
0.0055  0
0.0060 2.53787E-36
0.0065 4.53838E-28
0.0070 7.90870E-22
0.0075 4.60489E-17
0.0080 2.27444E-13
0.0085 2.32820E-09
0.0090 3.80753E-08
0.0095 2.48905E-05
0.0100 6.76525E-04
0.0105 6.50982E-04
0.0110 7.32045E-03
0.0115 1.29870E-01
0.0120 2.14734E-01
0.0125 7.89059E-01
0.0130 2.81979E+00
0.0135 8.54959E+00
0.0140 2.12839E+01
0.0145 4.84736E+01
0.0150 9.98039E+01
0.0155 1.89155E+02
0.0160 3.34992E+02
0.0165 5.51036E+02
0.0170 8.70073E+02
0.0175 1.29511E+03
0.0180 1.86130E+03
0.0185 2.58252E+03
0.0190 3.45899E+03
0.0195 4.51790E+03
0.0200 5.74212E+03
0.0205 7.10781E+03
0.0210 8.70630E+03
0.0215 1.03834E+04
0.0220 1.22547E+04
0.0225 1.41938E+04
0.0230 1.62758E+04
0.0235 1.83238E+04
0.0240 2.05871E+04
0.0245 2.27133E+04
0.0250 2.48106E+04
0.0255 2.70535E+04
0.0260 2.92121E+04
0.0265 3.12390E+04
0.0270 3.33473E+04
0.0275 3.52724E+04
0.0280 3.72598E+04
0.0285 3.89947E+04
0.0290 4.07637E+04
0.0295 4.22247E+04
0.0300 4.36956E+04
0.0305 4.51762E+04
0.0310 4.62913E+04
0.0315 4.75532E+04
0.0320 4.85658E+04
0.0325 4.95373E+04
0.0330 5.03755E+04
0.0335 5.11067E+04
0.0340 5.17434E+04
0.0345 5.23314E+04
0.0350 5.27595E+04
0.0355 5.31692E+04
0.0360 5.34815E+04
0.0365 5.36802E+04
0.0370 5.38625E+04
0.0375 5.39485E+04
0.0380 5.40203E+04
0.0385 5.39978E+04
0.0390 5.39147E+04
0.0395 5.38207E+04
0.0400 5.36686E+04
0.0405 5.34596E+04
0.0410 5.32113E+04
0.0415 5.29090E+04
0.0420 5.26018E+04
0.0425 5.22902E+04
0.0430 5.18971E+04
0.0435 5.15484E+04
0.0440 5.11055E+04
0.0445 5.06928E+04
0.0450 5.02196E+04
0.0455 4.97774E+04
0.0460 4.92918E+04
0.0465 4.87643E+04
0.0470 4.82981E+04
0.0475 4.77767E+04
0.0480 4.72306E+04
0.0485 4.67309E+04
0.0490 4.61933E+04
0.0495 4.56191E+04
0.0500 4.50884E+04
0.0505 4.45276E+04
0.0510 4.39724E+04
0.0515 4.34214E+04
0.0520 4.28426E+04
0.0525 4.23043E+04
0.0530 4.17376E+04
0.0535 4.11770E+04
0.0540 4.06226E+04
0.0545 4.00416E+04
0.0550 3.94994E+04
0.0555 3.89313E+04
0.0560 3.83698E+04
0.0565 3.78146E+04
0.0570 3.72656E+04
0.0575 3.67225E+04
0.0580 1.23163E+05
0.0585 3.56251E+04
0.0590 3.50996E+04
0.0595 1.88026E+05
0.0600 3.40095E+04
0.0605 3.34735E+04
0.0610 3.29431E+04
0.0615 3.24184E+04
0.0620 3.18991E+04
0.0625 3.13850E+04
0.0630 3.08510E+04
0.0635 3.03473E+04
0.0640 2.98484E+04
0.0645 2.93304E+04
0.0650 2.88176E+04
0.0655 2.83319E+04
0.0660 2.78289E+04
0.0665 2.73305E+04
0.0670 7.95528E+04
0.0675 2.63477E+04
0.0680 2.58629E+04
0.0685 2.53824E+04
0.0690 3.88928E+04
0.0695 2.39214E+04
0.0700 2.09638E+04
0.0705 2.06428E+04
0.0710 2.03035E+04
0.0715 1.99791E+04
0.0720 1.96530E+04
0.0725 1.93095E+04
0.0730 1.89802E+04
0.0735 1.86343E+04
0.0740 1.83022E+04
0.0745 1.79541E+04
0.0750 1.76193E+04
0.0755 1.72691E+04
0.0760 1.69182E+04
0.0765 1.65799E+04
0.0770 1.62271E+04
0.0775 1.58738E+04
0.0780 1.55325E+04
0.0785 1.51777E+04
0.0790 1.48223E+04
0.0795 1.44665E+04
0.0800 1.41103E+04
0.0805 1.37538E+04
0.0810 1.33969E+04
0.0815 1.30397E+04
0.0820 1.26925E+04
0.0825 1.23345E+04
0.0830 1.19764E+04
0.0835 1.16182E+04
0.0840 1.12507E+04
0.0845 1.08927E+04
0.0850 1.05345E+04
0.0855 1.01766E+04
0.0860 9.81862E+03
0.0865 9.46077E+03
0.0870 9.10319E+03
0.0875 8.74571E+03
0.0880 8.38856E+03
0.0885 8.02516E+03
0.0890 7.66889E+03
0.0895 7.31300E+03
0.0900 6.95752E+03
0.0905 6.59716E+03
0.0910 6.24292E+03
0.0915 5.88924E+03
0.0920 5.53613E+03
0.0925 5.17944E+03
0.0930 4.82790E+03
0.0935 4.47707E+03
0.0940 4.12365E+03
0.0945 3.77464E+03
0.0950 3.42647E+03
0.0955 3.07668E+03
0.0960 2.73057E+03
0.0965 2.38544E+03
0.0970 2.03966E+03
0.0975 1.69685E+03
0.0980 1.35403E+03
0.0985 1.01373E+03
0.0990 6.74065E+02
0.0995 3.36438E+02
0.1000 2.80147E+01
si2 h -2.5 2.5
sp2 0 1
si3 h 22.5 27.5
sp3 0 1
c ******************************************************************************
c
c ***************************internal source definition ************************
c ******************************************************************************
nps 10e7
c ------------------------------------------------------------------------------
*f106:p (10<555)  $rbm *f126:p (12<555)$ colon
*f146:p (14<555)  $lung *f166:p (16<555)$ stomach
*f186:p ((18 19)<555)  $breast (adipose tissue) *f206:p (20<555)$ ovary
*f226:p (22<555)  $bladder *f246:p (24<555)$ oesphagus
*f266:p (26<555)  $liver *f286:p (28<555)$ thyroid
*f306:p (30<555)  $bone *f326:p (32<555)$ brain
*f346:p (34<555)  $salivary glands *f366:p (36<555)$ skin
*f386:p (38<555)  $Adrenals *f406:p (40<555)$ ET region
*f426:p (42<555)  $Gall bladder *f446:p (44<555)$ Heart
*f466:p (46<555)  $Kidneys *f486:p (48<555)$ Blood (Lymphatic nodes)
*f506:p (50<555)  $Muscle *f526:p (52<555)$ Oral mucosa
*f546:p (54<555)  $Pancreas *f566:p (56<555)$ Uterus
*f586:p (58<555)  $Small intestine *f606:p (60<555)$ Spleen
*f626:p (62<555)  $Thymus *f646:p (64<555)$ Eyes
*f666:p (66<555)  $Lens *f686:p (68<555)$ Spinal cords
*f706:p (70<555)  $Teeth *f726:p (72<555)$ Tongue
*f746:p (74<555)  $Tonsils *f766:p (76<555)$ Trachea
*f786:p (78<555)  $Bronchi *f806:p (80<555)$ Ureter
*f826:p (82<555)  $Pallopian tubes *f846:p (84<555)$ Vagina
*f906:p (90<555)  $Residual tissue *f996:p 401 *f986:p255 ------------------------------------------------------------------------------- read file=HDRK-Woman_mat noecho m101 82000 1.0$lead
m401  6000  1.0                                                                  $C m201 8000 0.2 7000 0.8$vacuum
m301   6000 -0.000124                                                            $C 7014 -0.755636$N
8016 -0.231475                                                            $O 18000 -0.012889$Ar

Last edited by a moderator: Mar 4, 2015
2. Mar 7, 2015

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?